This invention is directed to an electronic timepiece frequency regulation circuit and in particular to the advancing and/or retarding of the phase of the frequency in an electronic timepiece to thereby effect frequency regulation thereof.
The component in an electronic timepiece most responsible for the accuracy obtainable thereby is the time standard. The development of the quartz crystal vibrator, and the use thereof in an electronic timepiece oscillator circuit to provide a highly stable high frequency time standard frequency on the order of 32.768 KHz has largely contributed to such accuracy. Nevertheless, although manufactured by the same process under the same conditions, the frequency at which such quartz crystal vibrators oscillate has been found to be highly and unexpectedly varied.
It has therefore been necessary to regulate the frequency of the oscillator circuit by effecting mechanical changes to the vibrator itself such as removal of mass from the electrodes of the vibrator, or the changing of the circuit design of the oscillator circuit. Additionally, the fine adjustment of the frequency is effected by a trimmer arrangement, usually in the form of one or several adjustable capacitors, for permitting an accurate adjustment of the high frequency time standard signal produced by the oscillator circuit. Such trimmer arrangements are capable of varying the high frequency time standard over a range of 1 Hz when the high frequency time standard signal required is 32.768 KHz. Thus, when the quartz crystal vibrator oscillates at frequencies which are not within 0.5 Hz above and below the 32.768 KHz time standard value, such vibrators are unacceptable for use in an electronic timepiece. Accordingly, to provide such a quartz crystal vibrator within 0.5 Hz of the high frequency time standard required for accurate operation of an electronic timepiece, numerous manufacturing processes and considerable expense are required to produce such a quartz crystal vibrator.